#include <stdio.h>
#include <math.h>
int main()
{
    int a, b, c = 0;
    printf("请输入a和b和c的值:");
    scanf("%d %d %d", &a, &b, &c);
    if (a + b < c && a + c < b && b + c < a)
    {
        printf("不能构成三角形\n");
    }
    else
    {
        double p = (a + b + c) / 2;
        double area = sqrt(p * (p - a) * (p - b) * (p - c));
        printf("三角型的面积是:%.2lf\n", area);
    }

    return 0;
}
